The correction of errors by typists has been a continuing problem for as long as typewriters have existed and the most common technique for correcting errors made by a typist is to use a small slip of correction material positioned and hand-held between the typing ribbon and printed page to cover up or camouflage the error. More recently, hand-held adhesive tabs which may be utilized in much the same way act to adhere to and remove the typed image from the page when the image has been typed with a specially formulated correctable ribbon.
The use of hand-held slips or tabs is generally quite inefficient since they are difficult to insert between the printing ribbon and the printed page, difficult to hold in that position while typing, particularly for multiple corrections, and subject to requiring a multiple correction effort if the portion of the correction material used has been previously used.
Automated correction of typing errors has been accomplished in recent years by the introduction of correcting typewriters such as the IBM Correcting SELECTRIC typewriter which solves many of the above problems but provides a solution to such problems only upon those dedicated typewriters which were designed and built to be correcting typewriters.
There exists a large number of typewriters such as the IBM SELECTRIC typewriter having a moving print carriage which do not have the automated correcting capability and which still have a significant useful life remaining. These typewriters and their operators will benefit from some efficient form of error correction.
U.S. Pat. No. 3,834,512 to Dorothy E. Haugen discloses an apparatus for converting a typebar typewriter of conventional construction into a typewriter having the capability of improved correction. This device is permanently mounted on the typewriter to position a span of correction material in proximity to the print point and includes a device for effecting the raising of the span of correction material to a point to where it traverses the print point for correction.
This device is cumbersome in that it requires a substantial amount of space on either side of the print point which cannot be interfered with at any time during the operation of the machine.